Underwater Metal Fatigue Detection For Ship Using PWM Based Eddy Current via Lab View

Project Title

Underwater Metal Fatigue Detection For Ship Using PWM Based Eddy Current via Lab View

Project Area of Specialization Electrical/Electronic EngineeringProject Summary

An investigation was performed into the effects of operating an absolute eddy-current testing (ECT) probe at frequencies close to its electrical resonance. A previously undocumented defect signal enhancement phenomenon, resulting from associated shifts in electrical resonant frequency, was observed and characterized. Experimental validation was performed on three notch defects on a typical aerospace super alloy, Titanium 6Al–4V. A conventional absolute ECT probe was operated by sweeping through a frequency range about the electrical resonance of the system (15 MHz). The phenomenon results in signal-to-noise ratio (SNR) peak enhancements by a factor of up to 3.7, at frequencies approaching resonance, compared to those measured at 1 MHz the defect signal enhancement peaks are shown to be a result of resonant frequency shifts of the system due to the presence of defects within the material. A simple, operational approach for raising the sensitivity of conventional industrial eddy current testing is proposed, based on the principles of the observed near electrical resonance signal enhancement (NERSE) phenomenon. The simple procedural change of operating within the NERSE frequency band does not require complex probe design, data analysis or, necessarily, identical coils. Therefore, it is a valuable technique for improving sensitivity, which complements other ECT methods and feasible solution for under water metal fatigue detection for Ship.

Project Objectives

The Objective of this is to provide a scientific contribution to the understanding of PWM-method for the purpose of utilizing it for industrial use. The primary focus is on the under water metal fatigue detection for Ship using PWM based eddy current via lab view/MATLAB or oscilloscope

• To design a system to generate eddy current using PWM (Pulse Width Modulation) technique
• To design exact no of turns of coils to operate the phenomena.
• To make it possible and display result on GUI of Lab view/MATLAB

Project Implementation Method

The first section is the Excitation of the ECT probe which includes multi-frequency oscillators, multiplexer and the current pump. This excitation is implemented using multiple sinusoidal oscillators capable of constantly driving the Improved Howland Current Pump at different frequencies. This selection includes a multiplexer specially designed to choose the desired test frequency. As a result, the system can test the material at various depths corresponding to the selected frequency. The current pump excites the ECT probe and allows effective testing of the metal specimen. Numerical design of the probe allows better accuracy and efficiency. Whenever a crack is present on a metal specimen, change in impedance causes a phase shift between the input and output signals of the probe. These signals are prepared and demodulated to extract the required crack information. Demodulation at this stage involves extracting both the amplitude and phase information of the crack. Using embedded hardware based design; the results can be received on spot which greatly increases the portability. A touch screen is used for real time plotting. Data comparison feature at different test frequencies is also incorporated.         

Benefits of the Project

As already discussed that we are working on Metal Fatigue Detection so our system is usable in firm where

• Automotive Industries
• Aircraft Industries
• Inspection of jetty support legs
• Underwater and through marine growth: sheet piling
• Elsewhere metallic Fatigue is not compromised

Technical Details of Final Deliverable

This project will focus on improvement in the sensitivity of the design to be able to detect even smaller cracks and reliable design to reduce noise from acquired signals.

Final Deliverable of the Project Hardware SystemCore Industry TransportationOther Industries Manufacturing Core Technology OthersOther Technologies Shared EconomySustainable Development Goals Industry, Innovation and InfrastructureRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	30497
Raspberry pi	Equipment	1	9000	9000
Coils	Equipment	3	499	1497
Power Transistor	Equipment	2	200	400
Relays	Equipment	5	100	500
Diodes	Equipment	2	100	200
Metal sheets	Equipment	2	1000	2000
Power supply unit	Equipment	1	100	100
Opa548	Equipment	1	3000	3000
RF-2713	Equipment	2	400	800
IC Mux	Equipment	2	1500	3000
Casing	Miscellaneous	1	5000	5000
other	Miscellaneous	1	5000	5000